This proposal focuses on defining how energy regulation alters normal and malignant hematopoietic stem/progenitor (HSPC) function. Our preliminary data indicate that there are specific enzyme regulators of cell metabolism that selectively and differentially affect normal and malignant HSPC. The studies to date have included focused manipulation of pyruvate kinase isoforms (PK-M1 and -M2) implicated in the Warburg effect of solid tumors using engineered mouse models. These studies indicate that normal HSPC are advantaged in competitive repopulation experiments in the absence of PK-M2. In striking and potentially therapeutically useful distinction, leukemogenesis with Bcr-Abl is markedly inhibited in the absence of PK-M2. These studies are the basis for a more detailed understanding of the metabolic parameters governing the phenotypic changes and examination of whether the distinctions are leukemogeneic allele-specific. Based on the findings above, we also embarked on a forward shRNA screen to evaluate other metabolic enzymes and their differential effects on normal and malignant HSPC. Seven additional candidates were identified, including at least one thought to be downstream of the PK-M2 isoform. Studying the impact of these enzymes alone and in conjunction with PK-M2 to assess potential epistasis is proposed as a means to define new and potentially additive metabolic vulnerabilities of the leukemic cell that may spare normal HSPC function. These studies offer the potential for both new understanding of the metabolic governance of stem cells and new targets to influence the competitive relationship of normal and leukemic cells to the advantage of the normal cells. PUBLIC HEALTH RELEVANCE: Cellular energetics controlling normal and malignant hematopoietic stem/progenitor cells are distinctive and point to novel means of intervening to competitively advantage normal cells. Using genetic tools in mouse models, we propose defining in-depth unique metabolic vulnerabilities of leukemic cells.